If an application has received focus from the window manager, but doesn't
reassign focus to a child window before closing its focus window, focus can
temporarily revert to PointerRoot before the window manager gives focus to
another window. During PointerRoot focus, the window until the pointer has
focus even if it is an override-redirect window.
--HG--
extra : rebase_source : 3c005183f4602346ce9068b4a87af068f0e82372
68cbf0e6c0